On 9/4/2011 8:06 PM, Michael G. Carper wrote:
> My goal is simple - make DXCC on 160m within the next 2 years.
That's a very ambitious objective. It took me three seasons to do it
when I moved from Chicago to CA, and two more years to get the
confirmations. It's much easier from W9 than from W6, but it's still
very ambitious. I'm using an 86 ft Tee vertical (see below) with 70+
radials, Beverages for four directions, and 1.5kW.
>
>
>
> So I'm looking for some advice about the antenna.
>
>
>
> I'm very tempted to buy a B&W folded dipole and call it done.
LOUSY choice. For one thing, that resistor burns half the transmitter
power. For another, 70 ft is very low for a horizontal 160M antenna.
> but I'm
> curious about what others are doing. I've got an amplifier, but no
> high-power tuner. So I want to avoid a tuner - the folded dipole seems to
> get me there and I can put it up at 70' or so in the elm trees.
>
>
For 160M you want a good vertical with a LOT of radials. If you can get
horizontal wires up 70 ft, use those rigging points to rig a top-loaded
Tee vertical. Make the vertical part as tall as possible, add
horizontal wires to bring the antenna to resonance. Why are you trying
to avoid a tuner? Is it cost? You're going to need to spend some money
on an antenna system that will work. A tuner is part of that cost.
Find a used Ten Tec 229B or 238, which are excellent tuners (manual)
that go for $275-$325.
There is great advice in the ARRL Handbook about radials, and how to get
the most bang for your buck with a given length of wire. A good
starting point is 30 radials, 70 ft long. #18 copper is about the
smallest wire that won't break. You can buy #14 THHN (house wire) for
about $35/500 ft at Lowe's and Home Depot, and there's a 10% discount
for buying five or six spools.
You are also going to need Beverage antennas to HEAR the DX. It sounds
like you have the space for that. They can be cheap to build if you
wind your own transformers, and you can feed them with virtually any
coax (like TV coax, or old RG58/59 that you have in your junk box). You
can let brush hold the wire above ground, and you can make supports by
cutting 1/2-in PVC conduit into 5 ft lengths, cutting small gauge rebar
into 3 ft lengths, sticking the rebar halfway in the ground, and sliding
the PVC over them. Drill a 1/4-in hole in the top of the PVC and use a
tie-wrap to secure the Beverage wire to the support. At your QTH,
you'll want at least four -- one pointed to EU that also gets you AF,
one to VK/ZL that also gets you Oceania, and another to JA and Asiatic
Russia.
> Thoughts?
Buy a copy of the ON4UN book and study it carefully. 160M is a fun
band, but it is not a CHEAP band if you want to work a lot of DX. No,
you don't need to spend money on Aluminum, but you will need to spend
some bucks on these simple wire antennas. To get those wires high in
the trees, look at the Big Shot, a super slingshot sold by Sherrill Tree
Service in NC. About $100, and a lot cheaper than paying folks to climb
those trees and install pulleys. You'll also need some good sun-proof
rope to hold those wires up. For more detailed advice on building and
rigging wire antennas in tall trees, see my website. I've got a half
dozen wires up 100-120 ft in tall redwoods, and in the process, learned
a lot about what keeps them up through heavy storms. One of them is a
160M dipole. My 86ft Tee vertical with 70+ radials consistently beats
it, often by a lot.
http://audiosystemsgroup.com/publish.htm
73, Jim K9YC
_______________________________________________
UR RST IS ... ... ..9 QSB QSB - hw? BK
|